Underground cistern where waste matter is made harmless using bacteria

Let's find possible answers to "Underground cistern where waste matter is made harmless using bacteria" crossword clue. First of all, we will look for a few extra hints for this entry: Underground cistern where waste matter is made harmless using bacteria. Finally, we will solve this crossword puzzle clue and get the correct word. We have 1 possible solution for this clue in our database.